1. Field
Embodiments described herein relate generally to a color signal processing circuit, a color signal processing method, and a television system.
2. Description of the Related Art
Conventionally, in an analog television broadcast receiver, a composite video baseband signal (CVBS signal) is obtained by demodulating an analog broadcast signal by a channel selection circuit and an intermediate frequency processing circuit. This demodulated video baseband signal is supplied to a color signal processing circuit, so that the color demodulation is performed.
In the conventional color signal processing circuit, the inputted composite video baseband signal is converted into a digital signal by an A/D converter. A color signal demodulation circuit in the color signal processing circuit is configured to obtain a color difference signal by applying AM demodulation processing, which uses a carrier based on the same clock signal as the clock signal used in the A/D converter, to the composite video baseband signal converted into the digital signal.
Note that Japanese Patent Application Laid-Open Publication No. 2000-156795 proposes an apparatus which automatically adjusts the frequency and phase of the sampling clock at the time of converting a video signal into a digital signal.
Here, there is no problem if the video signal has a sufficient level as an analog television signal inputted into the receiver. However, there is a case where since the radio-wave reception intensity is low, the amplitude of the analog television signal as a whole is small. In this case, there is a problem that when an image, which is based on the color difference signal demodulated by the color signal demodulation circuit, is projected, a stripe pattern may appear on the screen, thereby degrading video quality.